Papaver somniferum seed

Apologies for posting this twice but wasn't sure if it should go in 'problems' or 'plants'!

This year I have had several Papaver Somniferum plants pop up in my garden which I have allowed to flower. They are all about 3-4' high and most are fairly standard single flowers. A couple, however, are beautiful pom pom heads - one a lovely dusky pink/plum and the other a softest pink (looks like an old fashioned rose from a distance).

Does anybody know whether it is worth while collecting the seed from these 2 plants to sow for next year? Will they be true to the parent plant? The bees have been busy buzzing between them so if they are easily cross pollinated this is likely to have happened.

If cross pollination is a problem, would it be possible to prevent cross pollination of a couple of the unopened flower buds (perhaps by tiring some insect mesh loosely around them) in the hope of producing 'true' seed?